Field of Invention
The present invention relates to the fields of vacuum electronic technology, particle physics, and accelerators, and more particularly to a sheet electron beam/multi-electron beam metamaterial high-power microwave source, which is high-powered, high-efficient, miniaturized, easy to be manufactured, and liable to integrate with semiconductor devices.
Description of Related Arts
In the microwave frequency band, compared with the semiconductor devices, although vacuum electron devices have the high power and the high efficiency, the vacuum electron devices have the large volume, the heavy weight, and the poor consistency. With the rapid development of the semiconductor devices, the vacuum electron devices, such as the traveling-wave tube, the backward wave oscillator, the klystrons, and the magnetrons, are facing great challenges in the fields of communication, radar, guidance, electronic countermeasures, microwave heating, accelerators, and controlled thermonuclear fusions. Thus, the vacuum electron devices are urgently required to develop toward the miniaturization while further improving the output power, so as to meet the challenges from the semiconductor devices. Compared with the conventional vacuum electron devices, the sheet beam metamaterial high-power microwave source has the advantages of both the metamaterial and the sheet electron beam. Firstly, the resonance characteristic of the metamaterial leads to the high interaction impedance of the metamaterial slow-wave structure (SWS), so the sheet beam metamaterial high-power microwave source has the high power and the high efficiency. Secondly, the square metallic waveguide loaded with the metamaterial is able to work under the cut-off frequency of the empty waveguide, so the structure size of the sheet beam metamaterial high-power microwave source is greatly decreased, which contributes to the miniaturization of the vacuum electron devices. Thirdly, the sheet electron beam is able to transmit the high current with the small size, which further contributes to increasing the output power of the vacuum electron devices. Fourthly, the sheet electron beam is beneficial to expand the interaction area, so as to further increase the efficiency of the vacuum electron devices. Because the sheet electron beam/multi-electron beam metamaterial high-power microwave source has the advantages of both the metamaterial and the sheet electron beam, the sheet electron beam/multi-electron beam metamaterial high-power microwave source has the obvious advantages over the semiconductor devices in the competition of the higher frequency band (millimeter wave frequency band and terahertz frequency band). Thus, the sheet electron beam/multi-electron beam metamaterial high-power microwave source has attracted more and more attention of the scholars.
In 2005, the Spanish scholars, including Esteban, proposed a rectangular waveguide loaded with a two-dimensional metal rod array (one of the metamaterials) and illustrated that the rectangular waveguide is able to propagate the quasi transverse magnetic (TM) wave in principle (J. Esteban, et al., IEEE Trans. Microwave Theory Tech., 53 (4), 1506-1514, 2005). However, the structure of the rectangular waveguide has no natural electron beam channel and has the low interaction efficiency. Thus, the rectangular waveguide is not applicable in the vacuum electron devices. In 2014, the Chinese scholar Zhaoyun Duan and his American colleagues proposed a single-negative metamaterial built by a Complementary Electric Split Ring Resonator (CeSRR), as shown in FIG. 1. This metamaterial-loaded waveguide is able to propagate the quasi-TM wave and has the natural sheet electron beam channel (Z. Y. Duan, et al., Phys. Plasmas, 21 (10), 103301, 2014). Moreover, as shown in FIG. 2, the metamaterial-loaded waveguide can be regarded as a novel SWS with the high interaction impedance (more than 750 ohms), larger than the interaction impedance of the helix in the S band (about 100-200 ohms) and the interaction impedance of the coupled cavity in the S band (about 300-400 ohms). However, this work merely theoretically analyzes the high-frequency characteristics of the metamaterial SWS, not involving the nonlinear effect of the beam-wave interaction and the related components, such as the energy output devices, the cathode, and the collector. Hence, the work merely theoretically predicts that the CeSRR is able to serve as the high-power microwave source, and thus mainly focuses on the metamaterial SWS which is merely one of the components of the high-power microwave radiation source.